Add search fields to views

Make receptoraddress list views
searchable by "address"

Other changes:
- Add help text to source and target of the
InstanceLink model

Signed-off-by: Seth Foster <fosterbseth@gmail.com>

awx/main/models/ha.py

@@ -70,8 +70,8 @@ class InstanceLink(BaseModel):
         ordering = ("id",)
         constraints = [models.UniqueConstraint(fields=['source', 'target'], name='source_target_unique_together')]
 
-    source = models.ForeignKey('Instance', on_delete=models.CASCADE)
-    target = models.ForeignKey('ReceptorAddress', on_delete=models.CASCADE)
+    source = models.ForeignKey('Instance', on_delete=models.CASCADE, help_text=_("The source instance of this peer link."))
+    target = models.ForeignKey('ReceptorAddress', on_delete=models.CASCADE, help_text=_("The target receptor address of this peer link."))
 
     class States(models.TextChoices):
         ADDING = 'adding', _('Adding')